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– Michael E2Nov 23 '19 at 14:38

Given
$$\frac{x^{3x - 20} - x^x}{x^x - x} = x^x$$
then dividing by $x^x$ leads to
$$x^{2 x - 20} - x^x + x - 1 = 0.$$
Noticing $x=-1$ and $x=1$ are solutions then these should be expected results. For this version one could use the code

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